• Journal of Information Processing Systems
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• v.20 no.2
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• pp.239-251
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• 2024

Coronavirus disease 2019 (COVID-19) has severely curtailed travelers' willingness to carpool and complicated the psychological processing system of travelers' carpooling decisions. In the post-COVID-19 era, a two-stage decision model under dynamic decision scenarios is constructed by tracking the psychological states of subjects in the face of multi-scenario carpooling decisions. Through a scenario experiment method, this paper investigates how three psychological variables, travelers' psychological distance to COVID-19, anticipated regret, and experienced regret about carpooling decisions, affect their willingness to carpool and re-carpool. The results show that in the initial carpooling decision, travelers' perception gap of anticipated regret positively predicts carpooling willingness and partially mediates between psychological distance to COVID-19 and carpooling willingness; in the re-carpooling decision, travelers' perception gap of anticipated regret mediates in the process of experienced regret influencing re-carpooling willingness; the inhibitory effect of experienced regret on carpooling in the context of COVID-19 is stronger than its facilitative effect on carpooling willingness. This paper tries to offer a fact-based decision-processing system for travelers.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.229-232
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• 2003

A waste container, one of the key compartments in a multi-barrier system for a potential high level radioactive waste (HLW) repository in Korea ensures the mechanical stability against the lithostatic pressure of a deep geologic strata and the swelling pressure of the bentonite buffer. Also, it prohibits potential release of radionuclides for a certain period of time. before it is corroded by impurities. Even though the materials of a waste container is carefully chosen and all manufacturing processes are under heavy quality assurance, there might be a slight chance of intial defects in a waste container. Also, during the deposition of a waste container in a repository, there might be a chance of an incident affecting the integrity of a waste container. In this study, the FEP's and the scenarios over radiological impact of a potential initial waste container defect was developed. Then the total system performance assessment on this initial waste container failure (ICF) scenario was carried out by the MASCOT-K, one of the probabilistic safety assessment tools KAERI has developed. Results show that for the data set studied in this paper, the annual individual dose by the ICF scenario well meets the KINS regulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.10
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• pp.865-875
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• 2012

In this paper, we optimize antenna locations for a distributed antenna system (DAS) with distributed antenna (DA) ports equipped with multiple antennas under per-DA port power constraint. Maximum ratio transmission and scaled zero-forcing beamforming are employed for single-user and multi-user DAS, respectively. Instead of maximizing the cell average ergodic sum rate, we focus on a lower bound of the expected signal-to-noise ratio (SNR) for the single-cell scenario and the expected signal-to-leakage ratio (SLR) for the two-cell scenario to determine antenna locations. For the single-cell case, optimization of the SNR criterion generates a closed form solution in comparison to conventional iterative algorithms. Also, a gradient ascent algorithm is proposed to solve the SLR criterion for the two-cell scenario. Simulation results show that DAS with antenna locations obtained from the proposed algorithms achieve capacity gains over traditional centralized antenna systems.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.3
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• pp.169-177
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• 2021

In this paper, we propose a novel global navigation satellite system (GNSS) spoofing detection technique through an array antenna-based direction of arrival (DoA) estimation of satellite and spoofer. Specifically, we consider a sophisticated GNSS spoofing attack scenario where the spoofer can accurately mimic the multiple pseudo-random number (PRN) signals since the spoofer has its own GNSS receiver and knows the location of the target receiver in advance. The target GNSS receiver precisely estimates the DoA of all PRN signals using compressed sensing-based orthogonal matching pursuit (OMP) even with a small number of samples, and it performs spoofing detection from the DoA estimation results of all PRN signals. In addition, considering the initial situation of a sophisticated spoofing attack scenario, we designed the algorithm to have high spoofing detection performance regardless of the relative spoofing signal power. Therefore, we do not consider the assumption in which the power of the spoofing signal is about 3 dB greater than that of the authentic signal. Then, we introduce design parameters to get high true detection probability and low false alarm probability in tandem by considering the condition for the presence of signal sources and the proximity of the DoA between authentic signals. Through computer simulations, we compare the DoA estimation performance between the conventional signal direction estimation method and the OMP algorithm in few samples. Finally, we show in the sophisticated spoofing attack scenario that the proposed spoofing detection technique using OMP-based estimated DoA of all PRN signals outperforms the conventional spoofing detection scheme in terms of true detection and false alarm probability.

• Journal of The Korea Institute of Healthcare Architecture
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• v.20 no.3
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• pp.41-48
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• 2014

Purpose: At the moment, a lot of Public Hospitals in Korea have adopted 5 or 6 bedrooms as a standard multi-bedroom type. However 5-6 bedrooms have many problems related to inpatient satisfaction and nosocomial diseases. Therefore 4 bedroom is under considering for standard multi-bed room in Public Hospitals in Korea. This paper tries to prove that adoption of 4 bedroom in Public Hospitals has nothing to do with economic loss which is now an obstacle in adopting 4 bedrooms. Methods: 3 Methods have been used in this paper. 1) Comparative analysis between medical insurance fee and service cost for hospitalization has been conducted through literature survey. 2) Scenario analysis has been used for the estimation of inpatient number when 4 bedrooms are adopted in Public Hospitals. 3) Relation analysis between profit and proportion of 4 bedroom in Public Hospitals. Results: Adoption of 4 bedroom as a standard multi-bedroom in Public Hospitals has been proved to have nothing to do with the economic loss of hospitals. Implications: It is necessary to introduce and expand 4 bedrooms instead of 5-6 bedrooms in hospitals for the upgrade of hospital environment and easy control of cross infection in inpatient bedrooms.

• Structural Engineering and Mechanics
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• v.60 no.5
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• pp.781-794
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• 2016

Due to its relatively good safety performance and aesthetic benefits, laminated glass (LG) is increasingly being used as load-carrying members in modern buildings. This paper presents an experimental study into one applicational scenario of structural LG subjected to in-plane bending. The aim of the study is to reveal the in-plane behaviors of the LG beams made up of multi-layered glass sheets. The LG specimens respectively consisted of two, three and four plies of glass, bonded together by two prominent adhesives. A total of 26 tests were carried out. From these tests, the structural behaviors in terms of flexural stiffness, load resistance and post-breakage strength were studied in detail, whilst considering the influence of interlayer type, cross-sectional interlayer percentage and presence of shear forces. Based on the test results, analytical suggestions were made, failure modes were identified, corresponding failure mechanisms were discussed, and a rational engineering model was proposed to predict the post-breakage strength of the LG beams. The results obtained are expected to provide useful information for academic and engineering professionals in the analysis and design of LG beams bending in-plane.

• Journal of Distribution Science
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• v.17 no.8
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• pp.5-14
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• 2019

Purpose - This study aims to proposes a conceptual framework to segment multi-national products based on a Chinese consumer's perception of multi-national products, to find the role of consumer ethnocentrism (CET) in country of origin (COO) effects for Chinese, and to figure out how different dimension of CET Effects on purchase intention developed market and home country. Research design, data and methodology - This study selected a 2×2×2 factorial design for the hypothesis test based on the product category × combination of manufactured type × Ethnocentrism level. This study distinguishes products between luxury (Burberry) and non-luxury (Nike) products and choose combination of manufactured type (Spain vs India/ Spain vs China) in order to perform comparative studies. A total of 223 Chinese participated in the experiment. After being exposed to each scenario, participants were asked to respond to questions about brand preference and purchase intention Results - Regarding to luxury made in developed country, it is worth that exposing COO information to low level of ethnocentrism consumers. Regarding to non-luxury product made in emerging country, it makes it worse when COO information to high level of ethnocentrism consumers. Lastly, regarding to non-luxury product, patriotic consumers prefer to purchase product made in home country.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.211-216
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• 2009

As demands for high-definition television (HDTV) increase, the implementation of real-time decoding of high-definition (HD) video becomes an important issue. The data size for HD video is so large that real-time processing of the data is difficult to implement, especially with software. In order to implement a fast moving picture expert group-2 decoder for HDTV, we compose five scenarios that use parallel processing techniques such as data decomposition, task decomposition, and pipelining. Assuming the multi digital signal processor environments, we analyze each scenario in three aspects: decoding speed, L1 memory size, and bandwidth. By comparing the scenarios, we decide the most suitable cases for different situations. We simulate the scenarios in the dual-core and dual-central processing unit environment by using OpenMP and analyze the simulation results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.1805-1824
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• 2013

Recently, the use of wireless body area networks (WBAN) has been increasing rapidly in medical healthcare applications. WBANs consist of smart nodes that can be used to sense and transmit vital data such as heart rate, temperature and ECG from a human body to a medical centre. WBANs depend on limited resources such as energy and bandwidth. In order to utilise these resources efficiently, a very well organized medium access control (MAC) protocol must be considered. In this paper, a new, adaptive and energy-efficient MAC protocol, entitled isMAC, is proposed for WBANs. The proposed MAC is based on multi-channel communication and aims to prolong the network lifetime by effectively employing (i) a collision prevention mechanism, (ii) a coordinator node (WCN) selection algorithm and (iii) a transmission power adjustment approach. The isMAC protocol has been developed and modelled, by using OPNET Modeler simulation software. It is based on a networking scenario that requires especially high data rates such as ECG, for performance evaluation purposes. Packet delay, network throughput and energy consumption have been chosen as performance metrics. The comparison between the simulation results of isMAC and classical IEEE 802.15.4 (ZigBee) protocol shows that isMAC significantly outperforms IEEE 802.15.4 in terms of packet delay, throughput and energy consumption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12A
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• pp.1251-1260
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• 2008

Diffuse wireless optical communication offers more robust optical links in terms of coverage and shadowing than line-of-sight links. However, traditional diffuse wireless infrared (IR) transceiver systems are more susceptible to multi-path distortion and great power decrease, which results in limiting high-speed performance. Multi-beam is an effective technique to compensate for multi-path distortion in a wireless infrared environment. The goal of this paper is to analyze the transmission characteristics by replacing traditional diffuse system (TDS) which contains single wide angle transmitter and single element receiver by system consisting of three-beam transmitter and non-imaging receiver (TNS) attached with compound parabolic concentrator (CPC). In the simulation, we use the recursive model developed by Barry and Kahn and build the scenario based on 10 different cases which have been listed in Table 1. Moreover, we also check the reliability of the TNS diffuse link channel by BER test on the basis of different receiver positions and room sizes. The simulation results not only show the basic transmission characteristics of TNS diffuse link, but also are references to design more efficient and reliable indoor infrared transmission systems.